CN112228434A

CN112228434A - Clamping collar with fixing fingers

Info

Publication number: CN112228434A
Application number: CN202010668872.0A
Authority: CN
Inventors: 斯蒂芬·德里翁; 法布里斯·普雷沃
Original assignee: Etablissements Caillau SAS
Current assignee: Caillau SAS
Priority date: 2019-07-15
Filing date: 2020-07-13
Publication date: 2021-01-15
Also published as: FR3098881B1; DE102020118759A1; FR3098881A1; US11619330B2; JP2021014918A; US20210018121A1

Abstract

A clamping system for connecting first and second pipes (2, 4), opposite ends of the pipes having clamping surfaces projecting from the cylindrical outer surfaces of the pipes. The system includes a collar (10) including a band (12) clampable around the clamping surface, the band (12) having first and second sides (13A, 13B) defining an internal groove (14) therebetween adapted to receive the clamping surface. The collar carries at least one fixing finger (40, 40') having a free end portion projecting axially beyond the edge of the first side face (13A), the free end portion having a rib (42) configured to be fixed on the outside of the belt by means of a radially projecting element (62).

Description

Clamping collar with fixing fingers

Background

The present disclosure relates to a clamping system for connecting first and second pipes, opposite ends of the pipes having clamping surfaces projecting from a cylindrical outer surface of the pipes.

Clamping systems of this type are known, for example, from european patents EP 14514498 and EP 2598785.

In such a system, the collar comprises a band that can be clamped around the clamping surface of the tube. The band has sides between which an internal groove is defined in which a clamping surface of the tube is placed for clamping. Thus, the tubes remain clamped relative to each other. As shown in the above patents, it may be useful to pre-install the clamping system on the end of at least one pipe before clamping.

In order to allow pre-mounting on two pipes, EP 2598785 suggests that the clamping system comprises a washer fixed relative to the collar by means of a fastening lug, and comprises first and second pre-mounting lugs which can cooperate with the first and second pipes, respectively, to fix the washer, and thus the entire clamping system, relative to the respective clamping surfaces of the pipes prior to clamping. In this case, these pre-mounting lugs comprise short lugs which extend back over the frustoconical ring of the gasket to cooperate with the clamping surface of the tube which is placed between the band and the gasket. These pre-installation lugs also include long lugs that extend from the top of the gasket in the opposite direction to the gasket to mate with the clamping surfaces of the other tubes.

In EP 2598785, both types of lugs are elastically deformable. Such devices are generally satisfactory, but for some applications it is important to improve the reliability of the fixing of the lug with respect to the clamping surface, in particular for long lugs. In fact, for particularly long lugs it may be difficult to ensure the correct range of elastic deformation for certain clamping diameters, in particular large diameters over a range of 5 cm or more. On the one hand, it is necessary to ensure that the modulus of elasticity of the lugs is sufficiently high so that they have the desired elasticity to be able to elastically return to a position after the pipe has been deformed when engaged in the clamping system to ensure the pre-installation retention of the pipe. They must then have the necessary elastic response so as not to deform too easily when traction is applied in the direction of detachment of the tube from the clamping system. However, this elastic holding force is only useful in the pre-mounted state, before clamping. In the clamped state, on the contrary, without affecting the clamping quality, it is desirable that the lugs are deformed to press into the band of the collar. However, if the modulus of elasticity of the lugs is high, the latter feature may be difficult to achieve in some cases, particularly for large diameter collars. Furthermore, if the modulus of elasticity is too high, the engagement thrust required to clamp the lugs on the clamping surface of the tube may be high and difficult to achieve in the case of final installation.

Thus, although the system of EP 2598785 is satisfactory for a large number of applications, it is desirable to propose another solution that allows pre-mounting the clamping system at the end of the first pipe that is substantially free of the above-mentioned drawbacks, in particular for large-diameter collars.

EP 1451498 proposes a system that allows pre-installation with respect to a pipe, using pre-installation lugs also carried out by the belt through a washer with its own. The same problems as described above may also occur in pre-installation with respect to a single tube.

Other clamping systems are also known comprising a collar and a washer carried by the collar, the washer having an internal lug capable of being clamped within one of the tubes for pre-mounting the clamping system at the end of the tube. This may be useful to complete the system, as well as to allow pre-installation with respect to another pipe. For this purpose, the long lugs proposed by EP 2598785 can be used, but particularly for large-diameter collars, another solution is required, substantially free from the above-mentioned drawbacks.

Disclosure of Invention

Generally, there is a need for a clamping system that allows for a controlled fixation in a pre-mounted state with respect to a clamping surface of one of the tubes intended to be clamped.

Accordingly, the present disclosure relates to a clamping system for connecting a first pipe and a second pipe, the opposite ends of the first and second pipes having clamping surfaces projecting from the cylindrical outer surface of the pipes, the system comprising a collar comprising a band capable of being clamped around the clamping surfaces, the band having first and second sides defining an internal groove therebetween capable of receiving the clamping surfaces, the collar carrying at least one fixing finger having a free end portion projecting axially beyond the edge of the first side, the free end portion having a collar configured to be secured on the outside of the band by means of radially projecting elements.

Thus, when the first pipe is fitted into the clamping system, the fixing fingers are naturally in a standby condition to engage the elements projecting radially therefrom. Thus, once the first pipe has been fitted into the clamping system, no special operations are required to achieve the fixing.

Optionally, the clamping system comprises a centering surface axially outboard of the edge of the first side.

Optionally, the centering surface comprises at least one centering surface formed on the fixed finger.

Optionally, the collar carries at least one centering finger projecting axially beyond an edge of the first side face, and wherein the centering surface comprises at least one centering surface formed on the centering finger.

Optionally, the fixed finger has a ramp at the end of its free end portion.

Optionally, the fixing finger has at least one reinforcing rib.

Optionally, the centering finger has a ramp at the end of its free end portion.

Optionally, the centering fingers have at least one reinforcing rib.

Optionally, the clamping system comprises a washer supported by the collar, said washer comprising an annular portion placed inside the band and carrying the fixing fingers.

Optionally, the washer also carries centering fingers.

Optionally, the ribs are formed on pins cut into the fixed fingers and deformed radially.

The present disclosure also relates to a clamping system according to the present disclosure and a first pipe having a clamping surface protruding from its cylindrical outer surface in the vicinity of its free end, the first pipe further having a fixing protrusion on the other side of the clamping surface with respect to its free end, the rib cooperating with the fixing protrusion when the first pipe is fitted into the collar.

Alternatively, the fixing projection is formed on a transverse blade having a fastening portion by which it is fastened to the first pipe and a fixing portion which is radially straightened with respect to the fastening portion.

Optionally, the blade has two fixed portions and the collar carries two fixed fingers configured to cooperate with the fixed portions.

Optionally, the securing protrusion is configured to define an angular wedging of the clamping system with respect to the first tube.

Optionally, the blade has two shoulders forming radial stops for the fixed finger.

The present disclosure will be clearly understood and its advantages will be better apparent from reading the following detailed description of one embodiment, which is presented by way of non-limiting example.

Drawings

FIG. 1 is a perspective view of an assembly including a clamping system and two tubes according to the present disclosure.

Figure 2 shows a side view of two tubes pre-assembled due to the clamping system.

Fig. 3 is a view similar to fig. 1, showing a variation.

Fig. 4 shows a first tube suitable for this variant.

Fig. 5 is a detailed view showing a case where two pipes are pre-assembled using the clamping system according to this modification.

Fig. 6A is a schematic view of a half-section taken in a plane containing the fixed fingers of fig. 5, the plane defined by axis a and the diameter of the band passing through the fixed fingers.

Fig. 6B is a view similar to fig. 6A for modification.

Detailed Description

Fig. 1 and 2 are described first. As can be seen from these figures, the clamping system comprises a collar 10 and a washer 28 of the same type as described in EP 2598785, said collar cooperating with said washer to assemble the two

pipes

2, 4.

In the following, a "radially inner" element refers to an element oriented towards the axis a of two pipes placed end to end and is the element closest to this axis a with respect to the other elements, called "radially outer" elements, which refer to those elements oriented away from the axis a. It is also conceivable that the axes a of the two tubes are also the axes of the collars, more particularly the axes of the cuff bands, which are wound on themselves.

Furthermore, a second element will be considered to be "outside" or "axially outside" a first element if it is located beside the first element, that is, outside the axial slice taken by the first element.

The collar comprises a strip 12 defining a groove 14 in which a bearing surface 18 belonging to the first tube 2 and a bearing surface 20 belonging to the second tube 4, respectively, can be inserted. The recess and the bearing surfaces have such a shape that the clamping force of the strap of the collar forces the ends of the

tubes

2 and 4 towards each other. The grooves 14 are defined between a first side 13A and a second side 13B of the belt 12, which sides in this case define the branches of a V visible on an axial section. Thus, the band 12 has an advantageously V-shaped axial section, while the bearing surfaces 18 and 20 have a diameter that increases progressively towards the opposite free end of the tube and have a shape such as a truncated cone.

The band 12 has ends 12A and 12B, respectively, which are substantially radially straightened to form support lugs. These lugs are perforated to allow the rod 24A of the clamping screw 24 to pass through them. The head 24B of the screw is wedged against one of the supporting lugs (in this case lug 12B), while the nut 26 is fixed against the other supporting lug 12A. It will be appreciated that rotation of the nut in the screwing direction brings the bearing lugs closer to each other, thereby reducing the internal diameter of the collar, that is to say allowing the strap to be clamped. Of course, other ways of clamping the strip are also conceivable, for example a hook system, as described in particular in patent application FR 3008160.

The clamping system includes a washer 28 secured to the collar. The gasket may in particular be of the type described in EP 1451498.

This gasket 28 has a frustoconical annular portion 30 which can be inserted between the opposite ends of the two

pipes

2 and 4 when the two

pipes

2 and 4 are engaged in the clamping system. In practice, the gasket 28 is fixed with respect to the band, in this case with respect to its second side 13B, by means of the fastening lugs, so that an annular space is arranged between the second side and the gasket. The free end of the second pipe 4 carrying its bearing surface 20 is inserted into this annular space within the groove 14, while the free end of the first pipe 2 carrying its bearing surface 18 is inserted on the opposite side of the annular space with respect to the gasket, that is to say against the inner face of the frustoconical portion 30 of the gasket 28.

In this case, the end of the tube 4 is an inner flared portion, the inner periphery of its bearing surface 20 forming a flared portion. On the other hand, the free end of the first pipe 2 is a male end having, beyond its bearing surface 18, an outer periphery 23, the diameter of which gradually decreases towards the tip of the free end. The end portion 23 thus formed can therefore be inserted substantially in a form-fitting manner into the flared portion formed at the end of the tube 4. The frustoconical annular portion 30 of the gasket 28 may have an annular deformation 32 forming a seal between the inner surface of the flared portion 19 and the outer periphery 23.

The fastening of the washer 28 of the collar 10 and/or the preassembly of the clamping system comprising the collar and the washer on the tube 4 can be in the same way as in EP 1451498, i.e. by means of fastening lugs and/or preassembly lugs 34 with which the washer is equipped, these lugs being intended to hook the washer on the second side 13B of the band, while arranging the above-mentioned annular space, as described in EP 1451498.

Other modes of fastening the washer to the collar may be used. For example, the washer may have a fixing ring in which the shank of the screw 24 can engage, or one or several fixing lugs which are fixed on the edge of the band, for example by hooking or by pinching. Likewise, other modes of pre-mounting the clamping system with respect to the tube 4 may be used, for example by providing the washer with an internal lug or stud engaged in the tube 4 to abut against the inner surface of the tube 4.

The collar carries a fixing finger 40 having a free end portion projecting axially beyond the edge of the first side face 13A. For each finger, the free end portion has a rib 42 configured to be secured to the outside of the band by a radially projecting element. As will be shown below, the radially projecting element is in particular a fixed projection fixed to the first pipe 2. The inner surface 43 of the common portion of the fixed fingers forms a centring surface which extends axially beyond the edge of the first side face 13A while being radially included in the diametrical size of this edge. Taken together, the different centering surfaces define a diametral dimension equivalent to that defined by the top of the gripping surface 18 of the first pipe 2, in order to center the first pipe when it is inserted in the gripping system. It can be seen that the collar also carries centering fingers 50 which are similar to the fixing fingers except that they do not have ribs. However, for the fixation fingers, their inner surfaces 53 form a centering surface. It can be seen that the fixing and centering fingers have ribs 48 which are axially oriented and reinforce the fingers. Thus, the fixed fingers and the centering fingers have radial responsiveness, that is, they are relatively inflexible and can be elastically deformed radially over a small radial displacement by having a strong tendency to spring back. The fixing fingers and centering fingers also have flared ramps 49 at the ends of their free ends. These flaring ramps facilitate insertion of the first tube into the clamping system.

In this case, the fixing fingers 40 and the centering fingers 50 are carried by the washer 28, which is itself supported by the collar 10, as shown. More specifically, the fixing and centering fingers are carried by an annular portion 30 (in this case a frustoconical annular portion) of the gasket, which is placed inside the band 12 of the collar. The fixed fingers and centering fingers extend forward from the leading edge of the ring portion. Within the meaning of the present disclosure, the forward direction is a direction from the second side face 13B towards the first side face 13A. Thus, the fixing fingers and the centering fingers extend forward beyond the front edge of the side 13A. The forward direction is indicated by arrow F in fig. 1. In the unclamped state of the collar, the fixing and centering fingers may extend substantially axially forward from the front edge of the annular portion 30 of the washer 28. In particular, they may extend parallel to the axis a, at least in the common portion between their ends. However, in their portion attached to the gasket 28, they may be slightly corrugated radially outwardly to be closer to the bottom of the groove 14 of the band 12. Furthermore, the stiffening rib can only start at a short distance from the junction of the fixing and centering fingers with the washer, so as to allow a certain flexibility in this junction between the lug and the washer, while ensuring the aforementioned responsiveness, it being noted that the radially outer surfaces of the fingers can cooperate with the edge of the first side face to promote the elastic return of these fingers radially inwards. It will be appreciated that when clamping the collar, two tubes are connected simultaneously, these being used to deform the portion of the fingers connected to the gasket by being pressed against the bottom of the groove by the clamping surface 18.

As can be seen in fig. 1 and 2, the first tube has a fixing projection 62 which projects radially on its outer surface and is located on the other side of the clamping surface 18 with respect to the free end 2' of the first tube 2. More specifically, the fixing projection 62 is formed on the lateral fin 60 having a fastening portion 60A by which it is fastened to the first pipe and a fixing portion forming the fixing projection 62 and radially straightened with respect to the fastening portion 60A. In practice, the fastening portion is connected to the fixing portion by the step 60B. In this case, the transverse blades 60 have the shape of flat blades, the thickness of which is measured radially and the width of which is measured parallel to the axis a of the collar. More specifically, in the example shown, the transverse blade has two similar fixing portions 62, which in this case are placed at the two ends between which the fastening portion 60A extends.

In fig. 2 it can be seen that each of the two fixing fingers 40 cooperates with one of these fixing portions 62 by means of its fixing pin 42. In fig. 2, the two pipes are pre-assembled, the clamping system being pre-installed at the end of the second pipe 4 and at the end of the first pipe 2. In this case, the clamping collar is sufficient to complete the assembly of the two tubes. In this way, as described above, the fixing lug and the centring lug deform under the clamping action without interfering with the latter.

Referring to fig. 3 to 5, a modification will now be described. In contrast to the clamping system of fig. 1 to 2, the clamping system itself is unchanged. A variation of this variant is that the system is combined with a first pipe, allowing the angular wedging of the clamping system with respect to this first pipe. In fact, the transverse blades 70 carried by the first pipe 2 and on which the fixing portions 72 forming the fixing projections are formed differ slightly from the blades 60 described previously in that these fixing portions 72 are connected to their fastening portions 70A by steps 70B, said steps 70B extending radially outwards through radially projecting ears 70C. These ears are simply made by folding the transverse blades. As can be seen in fig. 5, the angular spacing of the ears 70C is adjusted so that in the pre-assembled state the ears extend between the two fixing fingers 40 and are fixed by their pins 42 on the front edge of the fixing portion 72. This allows to ensure the angular wedging of the second tube with respect to the clamping system.

The shaping of the

transverse blade

60 or 70 allows a particularly efficient preassembly. In fact, as shown, the thickness of the blade is radially oriented, while its width is axially oriented. The fixed finger is fixed to the leading edge of the fixed part of the blade, that is to say the edge furthest from the free end of the first tube. Any force separating the first tube from the locking system operates parallel to the width of the transverse vanes. Therefore, it is the direction in which the blade is less likely to deform. Thus, pre-assembly is particularly effective. The ears 70C of the leaves 70 form shoulders in the form of radial stops for the fixed fingers 40.

For the installation of the assembly comprising two tubes and the clamping system, the free end of the tube 4 is first engaged in the annular space arranged between the gasket 28 and the second side 13B of the band, so as to pre-install the clamping system around this free end, and then the free end of the tube 2 is engaged in the clamping system until the position shown in fig. 3 and 5 is reached.

During the assembly of the first pipe into the clamping system, the centering surface is allowed to cooperate with the top of the clamping surface of the first pipe so as to center it with respect to the clamping system. This facilitates the correct pre-mounting of the clamping system on the first tube and thus the centering of the two tubes with respect to each other. It is possible for the centering surface to be formed completely on the fixed finger by one or several centering surfaces formed on the centering finger (if provided). The retaining finger flanges can be made in a very simple manner by a simple partial cut in the finger releasing the folded-back lugs to form the radially inwardly folded pins 42. The pin is very simple to manufacture, without the need for adding material, while forming an effective claw, so that the fingers grip onto the radially protruding elements on the outer circumference of the first pipe.

Fig. 6A schematically shows the first tube 2, the second tube 4, the strip of collar 12, the gasket 28 and the transverse blades 40. The frustoconical portion 30 of the gasket 28 is located between the inner surface of the support surface 20 of the second pipe 4 and the outer surface of the frustoconical end portion 23 of the first pipe 2. On the one hand, the clamping system is pre-mounted on the second pipe 4, the pre-mounting lugs 34 of the gasket hooking the gasket on the strap 12 of the collar on the one hand and bearing on the outer surface of the clamping surface 20 on the other hand. On the other hand, the clamping system is also pre-mounted on the first pipe, the fixed finger 40 being fixed on the fixed portion 72 of the blade 70, the pin 42 being fixed against the front edge of the fixed portion. In this example, as shown in the previous figures, the fingers pass radially above the fixed portion 72 until hooking over the leading edge thereof.

Fig. 6B shows a variant which differs from fig. 6A in that the fixing fingers 40' pass radially below the fixing portion, which in this case is similar to the fixing portion 62. In fact, the fixing fingers 40' extend axially forward from the frustoconical portion 30 of the gasket, while maintaining a diametral dimension that allows radial passage under the fixing portion 62 during the insertion of the end of the pipe 2 in the clamping system. Thus, the radially outwardly directed securing pins 42' of the fingers 42 may hook over the front edge of the securing portion 62. The ramp 49 'formed at the free end of the finger 40' points inwardly. Fixing finger 40' may also be similar to fixing finger 40 in the previous figures, and in particular have a centering surface and reinforcing ribs.

As shown, the fixing protrusions may be formed on the lateral fins fastened to the first pipe. The blade is a very simple and therefore easy to manufacture geometric element. However, since there may be a contact surface between the first tube and the vane, its fastening may be very limited. The transverse orientation of the blade promotes an efficient fixation because of the possible separation forces operating axially and thus perpendicular to the main direction of the blade, in which direction the blade is less prone to deformation.

The clamping band and the washer and the fingers are preferably made of metal. In particular the gasket, can be made of strips of austenitic stainless steel, the thickness of which is in particular comprised between 0.1mm and 0.5mm, even between 0.2 and 0.4 mm.

Claims

1. Clamping system for connecting a first and a second pipe (2, 4), the opposite ends of the first and second pipe having clamping surfaces (18, 20) protruding from the cylindrical outer surface of the pipes, the system comprising a collar (10) comprising a band (12) capable of being clamped around the clamping surface, the band (12) having first and second side faces (13A, 13B), defining an internal groove (14) therebetween capable of receiving the clamping surfaces (18, 20), the clamping system being characterized in that the collar carries at least one fixing finger (40, 40'), the fixed fingers have free end portions projecting axially beyond the edge of the first side face, the free end portions having ribs (42, 42') configured to be fixed on the outside of the belt by means of radially projecting elements.

2. Clamping system according to claim 1, comprising a centering surface (43) axially outside the edge of the first side face.

3. The clamping system of claim 2, wherein the centering surface comprises at least one centering surface (43) formed on the fixed finger.

4. Clamping system according to claim 2, wherein the collar carries at least one centering finger (50) axially protruding beyond the edge of the first side face, and wherein the centering surface (53) comprises at least one centering surface formed on the centering finger.

5. Clamping system according to claim 1, wherein the fixing finger (40, 40') has a ramp (49, 49') at the end of its free end portion.

6. Clamping system according to claim 1, wherein the fixing finger (40, 40') has at least one reinforcing rib (48).

7. Clamping system according to claim 4, wherein the centering finger (50) has a ramp (49) at the end of its free end portion.

8. Clamping system according to claim 4, wherein the centering finger has at least one reinforcing rib (48).

9. Clamping system according to claim 1, comprising a washer (28) supported by said collar (10), said washer comprising an annular portion (30) placed inside said band (12) and carrying said fixing fingers (40, 40').

10. Clamping system according to claim 4, comprising a washer (28) supported by the collar (10), the washer comprising an annular portion (30) placed inside the band (12) and carrying the fixing fingers (40, 40') and at least one centering finger (50) axially projecting beyond the edge of the first side face, the centering finger (53) comprising at least one centering surface formed on the centering finger.

11. Clamping system according to claim 1, wherein the rib (42, 42') is formed on a pin cut in the fixed finger (40, 40') and is radially deformed.

12. An assembly comprising a clamping system according to claim 1 and a first tube (2) having, in the vicinity of its free end, a clamping surface (18) projecting from its cylindrical outer surface, the first tube further having, on the other side of its clamping surface (18) with respect to its free end (2'), a fixing projection (62, 72) with which the rib cooperates when the first tube is fitted into the collar.

13. The assembly according to claim 12, wherein the fixing projections are formed on a transverse blade (60, 70) having a fastening portion (60A, 70A) by which it is fastened to the first pipe and a fixing portion (62, 72) which is radially straightened with respect to the fastening portion.

14. The assembly of claim 13, wherein the blade has two fixed portions (62, 72) and the collar carries two fixed fingers (40, 40') configured to mate with the fixed portions.

15. The assembly according to claim 12, wherein the fixing projection (62, 72) is configured to define an angular wedging of the clamping system with respect to the first pipe (2).

16. The assembly of claim 15, wherein the vane (70) has two shoulders (70C) forming radial stops for fixing fingers (40, 40') carried by the collar and configured to cooperate with the fixing portion.